As a consequence of today's laptop computers, conference rooms, etc., often being equipped with multiple microphones or other similar audio input devices, stereo codecs will also more frequently be used. This expected increase in stereo codecs emphasizes the need for MIMO (multiple-input multiple-output) audio processing and, in particular, MIMO echo cancellation. However, there are certain fundamental difficulties inherent in a stereo setup, or in any arrangement involving more than one loudspeaker, that must be addressed.